Spiders - Natural History 1

Spiders are not insects. Spiders are arachnids but belong with the insects in the phylum arthropoda.
Spiders have four pairs of legs, rather than three pairs, as insects do.
There are usually two to three claws at the end of each of a spider's legs.
Spiders have two body parts. One part is the head and thorax, called the cephalothorax. The other part is the abdomen.
Spiders do not have wings or antennae.
Most spiders have eight small eyes at the front of the cephalothorax. Their eyes are only good at sensing changes in light.
In front of the mouth, a spider has two chelicerae, each with a fang on it.
Behind and below the mouth is another pair of mouthparts called pedipalps. They look like legs but serve as feelers and are used to taste and crush food prey.
The spider uses its fangs to inject poison and digestive juices into its prey. The food is then sucked into the spider's body as a liquid. Tarantulas feed on insects such as crickets, mealworms or cockroaches, and small vertebrates such as lizards, mice and birds.
Spiders use spinnerets at the tip of their abdomen to make silk threads.
One of the most common silk uses is the dragline. As some spiders move from place to place, they lay out a thin silk thread behind them. Just like a mountain climber, the spider uses the thread as a safety line. It can quickly backtrack on the line to get to safety.
Many female spiders will spin a thick, protective cocoon or egg sac for their developing eggs and spiderlings.
Spiders use their silk to make many types of webs to trap prey. Some types of webs are hammock webs, sheets of web, purse webs, and orb webs.
Orb weaving spiders hide near their web. A silk thread stretches from the web to the spider's hiding place. When a prey, such as a fly or moth is caught in the web and struggles, the silk thread vibrates. The spider feels the vibrations and rushes out to catch the prey. It bites and injects poison into the prey through its fangs. It wraps the prey in silk and later sucks out the digested juices from the prey's body.
Spiders can be found on tree trunks, in bushes, in grass, in basements, or in garages.
Tarantulas are the world's largest spiders.

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• spider
• arachnid
• tarantula
• cephalothorax
• abdomen
• pedipalps
• chelicerae
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• wildlife
• nature